<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8"/>
    <title>Xpath</title>
</head>
<body>
<ul>
    <li class="c1" id="l1">北京</li>
    <li id="l2">上海</li>
    <li id="c3">深圳</li>
    <li id="c4">武汉</li>
</ul>
</body>
</html>